Ecology



Ecology

The scientific study of the interactions among organisms and between organisms and their environments is called ecology. Ecologists, scientists who conduct research in ecology, test their hypotheses outdoors in the field as well as in the laboratory. Ecologists also use computer models to understand these complex interactions. Understanding ecology helps people make decisions about environmental issues, such as how best to manage forests, rivers, and other natural resources. An organism's environment consists of other organisms as well as nonliving factors. The prokaryotes, protists, animals, fungi, and plants in the environment are called biotic factors. The nonliving physical and chemical conditions are called abiotic factors. Ecologists study the relationships among biotic and abiotic factors at five increasingly broad levels: organisms, populations, communities, ecosystems, and the biosphere

1. What is ecology?

2. Why do people study ecology

3. What is the difference between biotic and abiotic factors?

Levels of Ecological Study The smallest unit of ecological study is the individual organism. A blue sweetlip fish is one example of an organism in a coral reef environment. A population is a group of individual organisms of the same species living in a particular area. A group of sweetlip fish in the reef environment is an example of a population. The coral reef is home to a collection of living things including fish, coral animals, microscopic algae, and all other organisms living in and around the reef. All of the organisms inhabiting a particular area make up a community. An ecosystem includes the abiotic factors and the biotic factors in an area. A coral reef ecosystem includes the reef's many species and its nonliving conditions, such as the water temperature and amount of sunlight. The broadest level of ecological study is the biosphere. The biosphere is Earth's thin, life supporting layer of air, soil and water. The biosphere extends to an altitude of several kilometers; the land to a depth of about 2 kilometers; lakes and streams; and the oceans to a depth of several kilometers. Energy enters the biosphere as solar radiation and exits in the form of heat.

4. List the five levels of ecological study in order from largest to smallest.

5. How does a population differ from a community?

6. How do a community and an ecosystem differ?

7. Explain why it is more accurate to define the biosphere as the global ecosystem than as the global community

Patchiness of the Biosphere

The biosphere is not spread out uniformly around the planet. Looking at Earth from a space shuttle, you would see that the biosphere is "patchy"—like a quilt of different environments, including land and oceans, lakes and ice. Zoom in closer to observe just one continent, and you would see an uneven distribution of ecosystems such as deserts, grasslands, forests, and rivers. A still smaller area, such as a wilderness, may contain patches of woods, fresh water, and marshes. All these environmental variations are due mainly to differences in abiotic factors such as temperature, soil type, and the availability of water and light. This patchiness creates a number of different habitats, or specific environments in which organisms live. Each habitat has characteristic abiotic and biotic factors. For example, a wilderness may include several habitats: patches of forest, marshy areas, and a river. The forest patches are home to trees and certain species of birds and animals. The marshy land areas provide a habitat for many species of prokaryotes, fungi, and insects that live in and on top of the wet soil. And within the river habitat is a surface "microhabitat" that supports floating plankton and swimming animals, while the deeper water is a separate microhabitat, with different light and temperature conditions and a different community of organisms. An animal’s niche is its way of life it pursues within its habitat. When it reproduces, the number of offspring, its predators, its prey all are parts of an animal’s niche.

8. Describe what is meant by the "patchiness" of the environment.

9. What is the difference between an organism’s habitat and an organism’s niche

Key Abiotic Factors.

The sun provides light and warmth and is the energy source for almost all ecosystems on Earth. Sunlight powers photosynthesis by plants, the main producers in most terrestrial (land) ecosystems.. In aquatic (water) environments, sunlight provides energy for photosynthetic producers such as algae. The fact that sunlight only penetrates a short distance into a body of water affects where algae live within a lake or ocean. Water is essential to all life on Earth. All organisms contain water—in fact, you consist of nearly 70 percent water! Among its many important properties, water can dissolve gases such as oxygen and solutes such as salt. Terrestrial organisms have adaptations that keep them from losing too much water and drying out. For example, some plants such as pine trees have needle-shaped leaves with a waxy coating. These leaves minimize the amount of water that evaporates into the air. Aquatic organisms also must balance their water uptake and water loss. Otherwise, their cells may burst or shrivel due to osmosis. Most life exists within a fairly narrow range of temperatures, from about 0°C to about 50°C. Few organisms can maintain an active metabolism below 0°C for long, and most organisms' enzymes are denatured (they lose their shape and stop working) above 50°C. However, extraordinary adaptations enable certain species to live at extreme temperatures. Some species of prokaryotes, for example, can thrive in hot springs as hot as 80°C and around deep-sea vents, which are even hotter. Soil is the product of abiotic forces (such as ice, rain, and wind) and the actions of living things (such as microorganisms, plants, and earthworms) on the rocks and minerals of Earth's crust. The structure and chemical makeup of soil greatly affect which organisms can grow there. Wind can affect the distribution and the activities of organisms in several ways. Wind moves clouds and rain over Earth's surface. Wind also stirs up water in ponds, lakes, and streams, creating currents that in turn bring up nutrients from the bottom. Many land plants depend on wind to help disperse their pollen and seeds.

10. List five abiotic factors and describe how each could influence a living thing..

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